MINOR: haproxy: Add `-cc` argument

This patch adds the `-cc` (check condition) argument to evaluate conditions on
startup and return the result as the exit code.

As an example this can be used to easily check HAProxy's version in scripts:

    haproxy -cc 'version_atleast(2.4)'

This resolves GitHub issue #1246.

Co-authored-by: Tim Duesterhus <tim@bastelstu.be>

diff --git a/doc/configuration.txt b/doc/configuration.txt
index 5b1768e89fff70b5732498873760b7831f77e55a..1fb6094aaede0dc8dcaeee93619281d1588225fb 100644 (file)
--- a/doc/configuration.txt
+++ b/doc/configuration.txt
@@ -802,6 +802,9 @@ Comments may be placed on the same line if needed after a '#', they will be
 ignored. The directives are tokenized like other configuration directives, and
 as such it is possible to use environment variables in conditions.
 
+Conditions can also be evaluated on startup with the -cc parameter.
+See "3. Starting HAProxy" in the management doc.
+
 The conditions are currently limited to:
 
   - an empty string, always returns "false"

diff --git a/doc/management.txt b/doc/management.txt
index b1ef55ec23d70920e1386e010a734aca527817ea..39c3a31604344d5610e4f25382eda3b3187a6e10 100644 (file)
--- a/doc/management.txt
+++ b/doc/management.txt
@@ -195,6 +195,10 @@ list of options is :
     to bind. The exit status is zero if everything is OK, or non-zero if an
     error is encountered. Presence of warnings will be reported if any.
 
+  -cc : evaluates a condition as used within a conditional block of the
+    configuration. The exit status is zero if the condition is true, 1 if the
+    condition is false or 2 if an error is encountered.
+
   -d : enable debug mode. This disables daemon mode, forces the process to stay
     in foreground and to show incoming and outgoing events. It must never be
     used in an init script.

diff --git a/include/haproxy/cfgparse.h b/include/haproxy/cfgparse.h
index 1c97a88b92a6176077059dff67be4cb24a69d678..51e5b9edfe28d4826d88d32e12e285027befc6e5 100644 (file)
--- a/include/haproxy/cfgparse.h
+++ b/include/haproxy/cfgparse.h
@@ -126,6 +126,7 @@ void free_email_alert(struct proxy *p);
 const char *cfg_find_best_match(const char *word, const struct list *list, int section, const char **extra);
 int warnifnotcap(struct proxy *proxy, int cap, const char *file, int line, const char *arg, const char *hint);
 int failifnotcap(struct proxy *proxy, int cap, const char *file, int line, const char *arg, const char *hint);
+int cfg_eval_condition(char **args, char **err, const char **errptr);
 
 /* simplified way to define a section parser */
 #define REGISTER_CONFIG_SECTION(name, parse, post)                            \

diff --git a/include/haproxy/global-t.h b/include/haproxy/global-t.h
index 1bdbc1bbc49476e913af184921945750b8f692f3..057d90e6185ca3fdb174e306388025b857c1b209 100644 (file)
--- a/include/haproxy/global-t.h
+++ b/include/haproxy/global-t.h
@@ -38,6 +38,7 @@
 #define        MODE_MWORKER_WAIT       0x100    /* Master Worker wait mode */
 #define        MODE_ZERO_WARNING       0x200    /* warnings cause a failure */
 #define        MODE_DIAG       0x400   /* extra warnings */
+#define        MODE_CHECK_CONDITION    0x800    /* -cc mode */
 
 /* list of last checks to perform, depending on config options */
 #define LSTCHK_CAP_BIND        0x00000001      /* check that we can bind to any port */

diff --git a/reg-tests/startup/check_condition.vtc b/reg-tests/startup/check_condition.vtc
new file mode 100644 (file)
index 0000000..7d3324b
--- /dev/null
+++ b/reg-tests/startup/check_condition.vtc
@@ -0,0 +1,13 @@
+varnishtest "Tests the -cc argument"
+
+#REQUIRE_VERSION=2.5
+feature cmd "$HAPROXY_PROGRAM -cc 'version_atleast(2.5-dev0)'"
+
+shell {
+    $HAPROXY_PROGRAM -cc "version_atleast(2.4)"
+    ! $HAPROXY_PROGRAM -cc "version_atleast(1024)"
+
+    $HAPROXY_PROGRAM -cc "streq(foo,'foo')"
+    $HAPROXY_PROGRAM -cc "streq(\"foo bar\",'foo bar')"
+    ! $HAPROXY_PROGRAM -cc "streq(foo,bar)"
+} -run

diff --git a/src/cfgparse.c b/src/cfgparse.c
index 0f8ad579d8654f39a23446fda59b742c9a0a687c..dc31ecae2aa09be3bb64eb1b7128e99c5122875e 100644 (file)
--- a/src/cfgparse.c
+++ b/src/cfgparse.c
@@ -1736,7 +1736,7 @@ static const struct cond_pred_kw *cfg_lookup_cond_pred(const char *str)
  * and only in this case), 0 if the condition is false, 1 if it's true. If
  * <errptr> is not NULL, it's set to the first invalid character on error.
  */
-static int cfg_eval_condition(char **args, char **err, const char **errptr)
+int cfg_eval_condition(char **args, char **err, const char **errptr)
 {
        const struct cond_pred_kw *cond_pred = NULL;
        const char *end_ptr;

diff --git a/src/haproxy.c b/src/haproxy.c
index 3ac6ed9cf0b509e4cbaca95705274618b52ddf88..60435002c405ab9b13033ff240839b0df9e73748 100644 (file)
--- a/src/haproxy.c
+++ b/src/haproxy.c
@@ -570,6 +570,7 @@ static void usage(char *name)
 #endif
                "        -q quiet mode : don't display messages\n"
                "        -c check mode : only check config files and exit\n"
+               "        -cc check condition : evaluate a condition and exit\n"
                "        -n sets the maximum total # of connections (uses ulimit -n)\n"
                "        -m limits the usable amount of memory (in MB)\n"
                "        -N sets the default, per-proxy maximum # of connections (%d)\n"
@@ -1464,6 +1465,7 @@ static void init(int argc, char **argv)
        struct proxy *px;
        struct post_check_fct *pcf;
        int ideal_maxconn;
+       char *check_condition = NULL;
 
        global.mode = MODE_STARTING;
        old_argv = copy_argv(argc, argv);
@@ -1619,6 +1621,12 @@ static void init(int argc, char **argv)
                                global.tune.options |= GTUNE_RESOLVE_DONTFAIL;
                        else if (*flag == 'd')
                                arg_mode |= MODE_DEBUG;
+                       else if (*flag == 'c' && flag[1] == 'c') {
+                               arg_mode |= MODE_CHECK_CONDITION;
+                               argv++;
+                               argc--;
+                               check_condition = *argv;
+                       }
                        else if (*flag == 'c')
                                arg_mode |= MODE_CHECK;
                        else if (*flag == 'D')
@@ -1752,7 +1760,7 @@ static void init(int argc, char **argv)
 
        global.mode |= (arg_mode & (MODE_DAEMON | MODE_MWORKER | MODE_FOREGROUND | MODE_VERBOSE
                                    | MODE_QUIET | MODE_CHECK | MODE_DEBUG | MODE_ZERO_WARNING
-                                   | MODE_DIAG));
+                                   | MODE_DIAG | MODE_CHECK_CONDITION));
 
        if (getenv("HAPROXY_MWORKER_WAIT_ONLY")) {
                unsetenv("HAPROXY_MWORKER_WAIT_ONLY");
@@ -1787,6 +1795,58 @@ static void init(int argc, char **argv)
 
        usermsgs_clr("config");
 
+       if (global.mode & MODE_CHECK_CONDITION) {
+               int result;
+
+               uint32_t err;
+               const char *errptr;
+               char *errmsg = NULL;
+
+               char *args[MAX_LINE_ARGS+1];
+               int arg = sizeof(args) / sizeof(*args);
+               size_t outlen = strlen(check_condition) + 1;
+
+               err = parse_line(check_condition, check_condition, &outlen, args, &arg,
+                                PARSE_OPT_DQUOTE | PARSE_OPT_SQUOTE | PARSE_OPT_BKSLASH,
+                                &errptr);
+
+               if (err & PARSE_ERR_QUOTE) {
+                       ha_alert("Syntax Error in condition: Unmatched quote.\n");
+                       exit(2);
+               }
+
+               if (err & PARSE_ERR_HEX) {
+                       ha_alert("Syntax Error in condition: Truncated or invalid hexadecimal sequence.\n");
+                       exit(2);
+               }
+
+               if (err & (PARSE_ERR_TOOLARGE|PARSE_ERR_OVERLAP)) {
+                       ha_alert("Error in condition: Line too long.\n");
+                       exit(2);
+               }
+
+               if (err & PARSE_ERR_TOOMANY) {
+                       ha_alert("Error in condition: Too many words.\n");
+                       exit(2);
+               }
+
+               if (err) {
+                       ha_alert("Unhandled error in condition, please report this to the developers.\n");
+                       exit(2);
+               }
+
+               result = cfg_eval_condition(args, &errmsg, &errptr);
+
+               if (result < 0) {
+                       if (errmsg)
+                               ha_alert("Failed to evaluate condition: %s\n", errmsg);
+
+                       exit(2);
+               }
+
+               exit(result ? 0 : 1);
+       }
+
        /* in wait mode, we don't try to read the configuration files */
        if (!(global.mode & MODE_MWORKER_WAIT)) {
                char *env_cfgfiles = NULL;